The present invention relates to a stamping device that is applicable to a box-making machine.
Outline of a corrugated cardboard box-making machine of the prior art having devices for cutting hand-holes or air holes in cardboard sheets is shown in FIG. 1. In the figure, reference character a designates a paper sheet feed section, reference characters b and c designate print sections and reference character d designates a paper sheet eject section. One example of a hand-hole cutting device of the prior art which may be provided, if necessary, in this cardboard eject section d, is illustrated in FIGS. 2 to 4 (Since an air-hole cutting device employs a similar system to the hand-hole cutting device, description of the air-hole cutting device will be omitted.). FIG. 2 is a perspective view, FIG. 3 is a side view, FIG. 4 is a view taken along line A--A in FIG. 3 as viewed in the direction of arrows, and FIG. 5 is a plan view of a corrugated cardboard sheet that has been processed by the corrugated cardboard box-making machine.
Slot cutting designated by reference character e in FIG. 5 is carried out when the sheet passes between shaft j in the section d in FIG. 1, hand-hole cutting designated by reference character f in FIG. 5 is carried out likewise when the sheet passes between the shaft j in the section d in FIG. 1, and fold line working (scoring) designated by reference character g in FIG. 5 is carried out when the sheet passes between shafts k and between shafts 1 in the section d in FIG. 1. In addition, reference character h designates a fold line (score) worked by another kind of machine in the preceding step of the process. In FIG. 1, a corrugated cardboard sheet m fed from the paper sheet feed section a passes through the print sections b and c (with regard to the printing, detailed description will be omitted), and when it passes between the shafts k and between the shafts 1 in the paper sheet eject section d, scoring as shown at g in FIG. 5 is carried out.
Furthermore, when it passes between the shafts j, slot cutting as shown at e in FIG. 5 is carried out, and at the same time, hand-holes as shown at f in FIG. 5 are cut by means of a hand-hole die cutting device p shown in FIGS. 2 and 3 which is provided on the same shafts and which is the subject matter of the present invention. Regarding the working devices (not shown) for the slots e, normally the respective slot cutting devices are preset for each given dimension of the box-making by push-button operations through the respective electro-mechanical systems. However, with regard to the hand-hole die cutting device p, it is necessary to manually carry out mounting, demounting and position setting of the device on the shafts j for each hand-hole to be cut, as shown in FIGS. 3 and 4.
Briefly describing the operations, the shafts j have a mechanism such that they may be rotated in timed synchronism with the sheet m when it passes between them. A knife r mounted on a split knife mount base q and a split anvil t mounted on an anvil mount base s are respectively clamped on shafts u and v by means of fastening bolts w. Thus, the sheet m passing between the anvil t and the knife r can be stamped or die cut with the shape and dimension of the knife r which has been preliminarily shaped into a predetermined dimension. Here, it is to be noted that the stamping or die cutting method (normally called "upside stamping or die cutting method" or "downside stamping or die cutting method" depending upon whether the mount position of the stamping knife is the upside or the downside of the sheet) is greatly related to preventing of print defects and cutting sharpness at the stamped portion, and it is common practice that either one of them is sacrificed depending upon the method selected by the machine manufacturer. That is, cutting sharpness is excellent on the anvil side face of the sheet, but on the contrary, print defects are liable to occur on the anvil side face.
In the above-described hand-hole die cutting device of the corrugated cardboard sheet box-making machine, in the case where it is intended to change the stamping method, that is, to change to the upside stamping method or to the downside stamping method, it is necessary to remount the entire device including the knife mount base q and the anvil mount base s. In the case of remounting the entire device as described above, due to the heavy weight of the mount bases and the like, remounting has been a difficult operation. In addition, since a slot cutting device of either an electromechanical setting type or an automatic setting type is mounted on the same shafts, in the case of mounting a manual type stamping device, the automatic setting operation for a slot cutting device becomes impossible. Thus, productivity is deteriorated due to the time required for setting. Furthermore, such an arrangement sometimes caused a breakdown due to a collision between parts within the machine, such as when an automatic setting is attempted while the stamping device is still mounted.
The present invention has been proposed for the purpose of eliminating the above-mentioned shortcomings of the prior art, and it is one object of the present invention to provide a novel stamping device in which component parts can be easily replaced according to the importance of the qualities of the products (i.e. printing or cutting sharpness). The device according to the present invention allows the setting time to be reduced which improves productivity. Furthermore, automation can be achieved which contributes to improvements in productivity by eliminating breakdown and reducing the time the operation is shutdown.
In order to achieve the aforementioned object, according to one feature of the present device, there is provided a novel stamping device in which at least one pair of common mount bases of the same shape and the same dimension for mounting a knife or an anvil are disposed on each of two shafts, so that either one of a knife and an anvil can be selectively remounted on the respective shafts.
According to the present invention, since the mount bases for the knife and the anvil are each formed in a common shape, there is a reduction in the number of component parts to be replaced, replacement can be achieved simply and easily, reduction in weight can be realized, also they can be formed as separate units, automatic setting is possible, and productivity can be improved by shortening the setting time.